RF Tuning Procedure for Transmitters using Exact V2 Exciter
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1. Introduction The Comark Exact exciter has a very capable / powerful non-linear digital pre-corrector contained in it. Knowing how to set up and properly adjust this corrector is key to the best performance and safe operation of a transmitter. Described below is a basic guide to allow a user to accomplish the proper tuning adjustment of this corrector. 2. Basic Setup First insure that the transmitter is properly connected to the output mask filter and load.
. Checking the Feedback Signals Levels Once the feedback signals are connected, the user can check, in the Exact Precorrections Menu, that they are properly wired, synchronized, and that their power levels are in accordance with the specifications. 5. Setting Crest Factor and Protection Clipping Parameters The only parameters that need to be set before launching the DAP are Crest Factor, Protection Clipping, and Timer (Correction Time). 6.
stretch peaks unless told otherwise. If this is not kept to a “reasonable” level it could result in amplifier damage. A good guideline is to keep this only about 3dB above the crest factor setting. Once correction has run, it should be adjusted down by 1dB from where it is set to see if there is a performance impact. If not, then leave it alone. It should only be carefully increased in small increments to see if increasing has any positive effect on signal performance.
10. Crest Factor Optimization Parameter Setting For a given “Crest Factor”, the “Crest Factor Optimization” enhances the signal shoulders. Finding the best value for this parameter allows the user to gain performance on the shoulders of the signal, thus optimizing the amplifier power. This shoulder optimization involves a MER / SNR performance reduction. The user must find the best trade-off for shoulder performance vs. MER/SNR performance.
